ci: fix GH actions trigger criteria

Author: pmmmwh

.github/workflows/ci.yml

@@ -2,9 +2,9 @@ name: CI
 
 on:
   pull_request:
-    types:
-      - opened
-      - synchronize
+  push:
+    branches:
+      - main
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number }}